2867 Šteins

2867 Šteins

Contrast-enhanced image of 2867 Šteins by Rosetta
Discovery
Discovered by	Nikolai Stepanovich Chernykh
Discovery site	Crimean Astrophysical Observatory
Discovery date	4 November 1969
Designations
MPC designation	(2867) Šteins
Named after	Kārlis Šteins
Alternative designations	1969VC
Minor planet category	Main belt
Orbital characteristics
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc	64.29 yr (23481 days)
Aphelion	2.7074 AU (405.02 Gm)
Perihelion	2.01961 AU (302.129 Gm)
Semi-major axis	2.36349 AU (353.573 Gm)
Eccentricity	0.14550
Orbital period	3.63 yr (1327.2 d)
Average orbital speed	19.27 km/s
Mean anomaly	325.187°
Mean motion	0° 16m 16.5s / day
Inclination	9.9348°
Longitude of ascending node	55.371°
Argument of perihelion	251.16°
Earth MOID	1.02856 AU (153.870 Gm)
Jupiter MOID	2.53104 AU (378.638 Gm)
Jupiter Tisserand parameter	3.515
Physical characteristics
Dimensions	6.67 × 5.81 × 4.47 km
Mean radius	2.65 km
Rotation period	6.049 h (0.2520 d)
Sidereal rotation period	6.05 h
Geometric albedo	0.34 ± 0.06
Temperature	~ 181 K
Spectral type	E
Absolute magnitude (H)	12.5

2867 Šteins is a small main-belt asteroid that was discovered in 1969 by Nikolai Chernykh. It is named after Kārlis Šteins, a Latvian and Soviet astronomer. Šteins was visited by the European Space Agency's Rosetta space probe in 2008.

A study published in 2006 by astronomers at the European Southern Observatory showed that Šteins is an E-type asteroid with a diameter of approximately 4.6 km. Studying the asteroid before its flyby, the ESA Rosetta space probe showed via a lightcurve analysis that Šteins has a rotation period of about six hours, is irregular in shape, and does not have any moons.

After the Rosetta flyby, the ESA described Šteins as 'a diamond in the sky', as it has a wide body that tapers into a point. The wide section is dominated by a large crater (2.1 km diameter), which surprised scientists, who were at first amazed the asteroid survived such an impact, while later it turned out that the ratio of crater diameter ${\displaystyle D}$ to asteroid size ${\displaystyle R}$ is with a value of ${\displaystyle D/R=0.79}$ in fact not abnormally large. The photographs of Šteins taken by Rosetta allowed scientists to determine that the asteroid has dimensions of 6.67 × 5.81 × 4.47 km, which equates to a mean diameter of 5.3 km.